Continuity mistake: When nurse Karen first enters the hospital and changes into her uniform, she's clearly shown putting on a dark belt (either black or brown). However, in her next scene with Mrs. Alves, as well as the scene where she's tricked into entering the hospital room to fool around with Bud, the belt is white.
Plot hole: Laurie is pounding on the door and screaming for help. But Loomis doesn't hear her for a full 20 seconds? It even shows him standing 30 feet from the door and he doesn't come running until Laurie has screamed for 20 seconds.
Continuity mistake: When Laurie leaves the hospital, she exits out of the hospital doors. Somehow the doors stay open. Later on in the far away shot, the doors are closed, then they are open again in the next shot.
Continuity mistake: Towards the end of the film, when Dr. Loomis finally finds out Michael is at the hospital and orders the trooper's car to turn around. As the car turns around, the lighting outside appears to be pre-dawn however they arrive at hospital and it is still pitch black.
Factual error: When Michael corners Laurie in the elevator, the door shuts just in time and slams on his hand and just keeps closing, and Michael pulls away. Elevators have rubber guards that would cause the door to open again if someone's hand would get caught in the closing.
Continuity mistake: When Pamela Susan Shoop is being killed by Michael in the spa, the towel is tied arround her upper chest, then the towel falls down, revealing her breasts. In the next shot a split second later the towel is back up at he upper chest.
Revealing mistake: At the end of the film, when Michael Myers is on fire walking out of the room in the hospital towards Laurie one can see that he is wearing gloves (probably so the actor will not be burned), but during the course of the entire movie, Michael Myers' hands are always visible.
Continuity mistake: When Michael falls off the balcony, he falls into some green grass and a garden is next to him. Yet in the original "Halloween", Michael falls onto the ground with barely any grass around him, just a dirt patch and no garden in sight. (This is explained because they reshot the ending to "Halloween" 1.).
Factual error: The story is supposed to take place on Halloween 1978, but some of the clothing and hairstyles have noticeable characteristics associated with the early 1980's; particularly those of Alice, Karen, and Darcy.
Continuity mistake: After getting out of the car, Laurie is on the ground beside Jimmy's car outside the hospital when she sees the Marshall's car pull up. When Loomis tells the Marshall he ought to handcuff him to the wheel, if you look, Jimmy's car is still visible in the distance, but Laurie is not in that shot.
Continuity mistake: In the scene where the boys ask Mr. Hunt about Ben Tramer, Mr. Hunt says that "it's just a little past 11." Following this up in the next scene Bud lures Karen into the room to kiss her and wish her Happy Halloween. During this scene, as Bud reaches up to kiss Karen, his watch is clearly visible and shows the time as 1:00.
Other mistake: When Jimmy finds Mrs Alves, he has to walk through the puddle of blood to get to her, but there are no footprints in the blood.
Continuity mistake: The flashing lights on the front of Bud and Jimmy's ambulance change places as they pull into the hospital driveway. They go from either the side of the hood to the front of the bumper.
Revealing mistake: In the storyline, Michael Myers is supposed to only be 21 years old. Towards the end of the movie, right before Michael kills Karen in the hot tub, he puts his hand on Karen's shoulder. It is easy to tell just by looking at his hand that he would be much older than 21. (The actor who played Michael was Dick Warlock, who at that time was in his early 40's).
Visible crew/equipment: The crash mat is visible when Michael Myers falls off the balcony in the beginning of the movie.
Revealing mistake: When Michael emerges on fire from the blown up room, if you look closely, you can see plain as day the moment when they light the stunt man on fire for the stunt. (Suddenly you see fire erupt in the shape of Michael's body.) And if you look VERY closely, shortly before this you can even briefly kind of see the stuntman playing Michael in the doorway waiting to be lit on fire. (The bottom half of his body is visible for a split-second a moment before they light him up).
Continuity mistake: Michael falls from the balcony in a different way from the first film.
Continuity mistake: Michael comes into Laurie's room and stabs at her bed, only to find pillows had been placed there. He then walks out and leaves the door open. When Jill returns from checking on a patient, the door is now closed and she opens it.
Factual error: The film takes place in Illinois on Halloween, October 31st, but you'd never know it by looking at the colors of the trees, they all have green leaves and there is almost no sign of Fall or ground leaves.
Revealing mistake: When Myers hits the hospital guard on his head with the hammer from behind we can see the head of the mannequin they used in place of the guard.
Answer: From what I have read: yes.
Alan Keddie